Weigh a conical flask. Using volumetric pipette #1 put 25.00 mL (see Note 1)
of the solution prepared in the previous step into the weighed conical flask.
Weigh the flask with the solution inside (note all the figures from your
balance!). Wash the flask, and reuse it for the next solution (you must weigh
the flask again!). But do not wash pipette #1 (see the Note 2 below how to
reuse it for the next solution).